Electrolyzing cobalt solutions



-Il'o Drawing.

PATENT OFFICE.

ELISHA BARTON CUTTEN, 0F KOKOMO, INDIANA.

ELECTROLYZING COBALT SOLUTIONS.

T 0 all whom it may concern:

Be it known that I, ELISHA B. CUTTEN, a citizen of the United States,and resident of Kokomo, county of Howard, State of In diana, haveinvented certain new and useful Improvements in Electrolyzing CobaltSo,- lutions; and I do hereby declare the follow ing to be a full,clear, and exact description of the invention, such as will enableothers skilled in the art to which it appertains to make and use thesame.

The invention relates to a method of separating and extracting the metalcobalt from solutions containing salts or cobalt by electrolysis. Manyattempts have been made heretofore to extract cobalt from ores andcompounds containing the same and to deposit the substantially puremetal by electrolysis, either to form a protecting coating for othermetals, or to admit of the deposited metal being recovered forsubsequent use but, so far as applicant is advised, none of theseattempts have been commercially successful, nor have any of thepreviously employed attempts to electrolyze solutions of cobalt saltsbeen found capable of practical application except for very brief runs,as the deposit tends to blacken after a short period of operation, or ithas been found that the efficiency of the method, measured by thepercentage of recovery or deposit, cobalt has fallen off so rapidly asto render the operation practically valueless from a commercialstandpoint. In most instances, the same mode of procedure has beenattempted, in respect of electrolyzation of cobalt, that has beensuccessfully practised in depositing nickel electrolytically, but,except in cases of relatively short runs, the results have been entirelyunsatisfactory and of no permanent commercial value.

I have discovered that the heretofore insurmounted difficulties in thesuccessful application of-electrolytic methods of the re covery anddeposition of cobalt have been due primarily to the lack of permanencyand stability of the electrolyte, due either to the presence of freeacid or alkali in the solution, or the production of acid or alkalineconditions therein during the electrolyzing operation.

I have discovered that all of these difiiculties may be obviated and anentirely satisfactory recovery and deposition of cobalt on a commercialscale and-without'any material falling off in efliciency, by theemployment Specification of Letters Patent.

Application filed October 20, 1919.

Serial No. 331,966.

of a neutral solution,-.of a suitable salt of cobalt, employed aselectrolyte, the neutrality being maintained constant throughout theoperation by the presence of a salt reagent that forms an insoluble andinnocuous precipitate with the liberated acid radical which is producedduring the electrolytic actlon.

A particularly efficacious arrangement which I have employed forcarrying out the new method includes an electrolyte consisting of asolution of sulfate of cobalt which is maintained in a constantlyneutral condition by the presence of calcium carbonate. The latter maybe added from time to time. or it may be applied in suitable quantitiesto maintain the neutrality of the electrolyte for a long time, therebyavoiding the re-- peated additions of the neutralizing agent. Entirelysatisfactory results have been had from the use of an electrolyte madeby dissolving about six ounces of sulfate of cobalt per gallon ofdistilled water, although relatively stronger or weaker solutions may beemployed as desired. Into the solution thus obtained, a small quantityof pure calcium carbonate is stirred, one-half ounce per gallon ofelectrolyte is generally sufiicient, to completely neutralize theelectrolyte and precipitate any foreign matter that may tend to obstructthe normal operation. This solution when filtered is ready for use. Theelectrolyte as thus constituted, works satisfactorily and produces abright uniform deposit of cobalt for a period of one or two days,provided the E. M. F. employed does not exceed one volt and ispreferably maintained at about eight tenths of a volt. As soon as thedeposit shows a tendency to blacken, a further quantity of calciumcarbonate is added to the electrolyte which immediately corrects thetendency and the normal bright deposit of cobalt is continued. In orderto avoid the necessity of repeated additions of the neutralizing agentto the electrolytic bath it has been found advantageous and effective tosurround the anode, preferably consisting of or containing cobalt, by aporous sack in which the neutral izing agent is contained, and which is,therefore, available for maintaining the electrolyte in a strictlyneutral condition for relatively long periods of operation.

In lieu of the-calcium carbonate as a neutralizing agent, bariumcarbonate may be employed, as the latter, like the calcium Patented Jline 29, 1920.-

salt, forms with the acid liberated during the electrolytic action, aninsoluble precipitate which is entirely innocuous and produces no effectwhatever upon the metallic deposit of cobalt and which offers no otherobjections than that it must be removed from time to time from theelectrolytic cell. I have also found .that oxid of cobalt or carbonateof cobalt may be employed as the neutralizing agent, and when the latteris employed, care must be taken that no caustic alkali, soda, potash, orammonia, is present to produce a double salt of cobalt, analogous to thedouble nickel salt employed in electrolysis of the latter metal, whichwould defeat the purposes of the present invention by causing adeposition of hydrogen at the cathode, which tends to alloy or mix withthe deposit of cobalt to the impairment of the latter. l

Instead of employing sulfate of cobalt as the electrolyte, the chloridof cobalt may be substituted and, if used, must be neutralized by theaddition of a salt which will produce an insoluble and innocuousprecipitate with the liberated hydrochloric acid radical, such carbonateof lead, which would result in the formation of lead chlorid and wouldbe in no wise harmful to the solution or the normal electrolytic action.

In carrying out the invention, therefore, it is necessary and desirablethat the elec trolyte be not only neutralized at the initiation of theelectrolytic action, but that it be maintained continuously neutral,which result may be effected by either adding successive portions of theneutralizing medium whenever the bath tends to show either an acid or analkaline condition, or surrounding the anode with a suitable poroussacking which contains a sufficient quantity of the neutralizing agentto maintain the electrolyte strictly neutral throughout a long andcontinued operation.

lVhat I claim is:

1. The method of depositing cobalt which includes in electrolyzing asolution of a suitable salt of cobalt, andmaintaining the neutrality ofthe electrolyte by the action of a reagent that forms an insoluble andinnocuous precipitate with the liberated acid radical.

2. The method of depositing cobalt which includes electrolyzing asolution of sulfate of cobalt, and maintaining the neutrality of theelectrolyte by the action of a reagent that forms an insoluble andinnocuous precipitate with the liberated sulfuric acid radical. l

3. The method of depositing cobalt which includes-electrolyzing asolution of sulfate of cobalt, and maintainin the neutrality of theelectrolyte by the presence of a carbonate which forms an insoluble andinnocuous precipitate with the liberated sulfuric acid radical.

4. The method of depositing cobalt which includes electrolyzing asolution of sulfate of cobalt, and maintaining the neutrality of theelectrolyte by the, presence of calcium carbonate.

In testimony whereof I allix my signature in presence of two witnesses.

ELISHA BARTON GUTTEN.

Witnesses: I

H. M. IVOYcHECK. S. K. HAUPERT.

